A recent analysis of more than 100 industry documents conducted by the Center for International Environmental Law (CIEL), a Washington, D.C.-based advocacy group, has revealed that the oil industry knew of the risks its business posed to the global climate decades before originally suspected.

It has also long been assumed that, in its efforts to deceive investors and the public about the negative impact its business has on the environment, Big Oil borrowed Big Tobacco’s so-called tactical “playbook.” But these documents indicate that infamous playbook appears to have actually originated within the oil industry itself.

If that is true, it would be highly significant—and damning for Big Oil—because the tactics used by the tobacco industry to downplay the connection between smoking and cancer were eventually deemed to have violated federal racketeering laws by a federal court. The ruling dashed efforts by Big Tobacco to find legal cover under the First Amendment, which just happens to be the same strategy that ExxonMobil and its GOP allies are currently using to defend the company against allegations of fraud. If the playbook was in fact created by the oil and gas industry and then later used by ExxonMobil, it ruins the company’s argument of plausible deniability, making it highly likely that the company violated federal law.

This latest development is a major blow to Big Oil, which has been trying to rebuff comparisons to the tobacco industry. It also comes as a group of state attorneys general are pursuing an investigation into possible fraud committed by ExxonMobil. The probe, which could ultimately extend to include other oil and gas companies, was launched in November by New York State Attorney General Eric Schneiderman, who has since been joined by 16 other state AGs in a historic national coalition seeking to find out if America’s largest oil company intentionally hid critical climate-related information about their future business from investors and the public.

Environmentalists and corporate accountability advocates have cheered the investigation, contending that ExxonMobil has engaged in a decades-long campaign of climate denial and deception, ultimately delaying action on climate change and putting the planet at risk.

“We began with three simple, related questions,” says Carroll Muffett, president of CIEL, about the recently analyzed documents, which are housed at the tobacco industry document archive at the University of California, San Francisco medical center. “What did they know? When did they know it? And what did they do about it? What we found is that they knew a great deal, and they knew it much earlier and with greater certainty than anyone has recognized or that the industry has admitted.”

Sowing seeds of doubt about climate science

“Big Oil created the organized apparatus of doubt,” Muffett said. “It used the same playbook of misinformation, obfuscation and research laundered through front groups to attack science and sow uncertainty on lead, on smog, and in the early debates on climate change. Big Tobacco used and refined that playbook for decades in its fight to keep us smoking—just as Big Oil is using it now, again, to keep us burning fossil fuels.” To wit: Exxon’s own Corporate Citizenship Report from last year revealed that the company is still funding climate denial groups.

The documents suggest that the tactics in question were developed by the Smoke and Fumes Committee, a group launched 70 years ago by the American Petroleum Institute, the national trade association that represents the U.S. fossil fuel industry, to study oil industry pollution and present its own spin to the public. If that is the case, it appears those same tactics were likely co-opted by the tobacco industry, which was later found guilty of committing fraud following a racketeering lawsuit filed in 1999 by the Department of Justice. The documents reveals that the deceptive actions taken by the oil industry so many decades ago prevented the possibility of early action on climate change—action that may have prevented potentially millions of climate-related deaths across the globe.

According to the Centers for Disease Control and Prevention, cigarette smoking is responsible for more than 480,000 deaths per year in the United States alone. The World Health Organization estimates that around 6 million people worldwide die from tobacco-related illnesses. Between 2030 and 2050, WHO estimates that climate change will cause approximately 250,000 deaths per year, from heat stress, malnutrition, malaria and diarrhea. That number does not include the deaths caused by climate-related natural disasters, which have more than tripled since the 1960s, resulting in over 60,000 deaths each year, mainly in developing countries.

Neva Rockefeller Goodwin, co-director of the Global Development and Environment Institute at Tufts University is also the great-granddaughter of John D. Rockefeller Sr., founder of the American oil giant Standard Oil Company, out of which ExxonMobil was born. Earlier this year, Goodwin decided to divest her shares of ExxonMobil stock and use the proceeds to fight climate change and climate denial. In an interview with AlterNet, she contrasted the impact of tobacco and fossil fuel:

In the large picture … tobacco and fossil fuel emissions are quite different. Tobacco kills people one by one. Climate change will increasingly cause events like hurricanes that will destroy large swathes of property, kill numbers of people, make many homeless. While it can be argued that smoking tobacco is a matter of individual choice, the production and use of fossil fuels is more obviously a social issue. In the long run, producers of fossil fuels will have to lose. The only question is how much the people and ecologies of the world will lose before our economies cease to make the situation worse.

U.N.: Climate change is “irreversible”

While the climate situation can certainly become worse, the actions of ExxonMobil and Big Oil have helped to put the planet on what many scientists are now saying is an unstoppable path. In 2014, the United Nations’ Intergovernmental Panel on Climate Change offered a grim assessment: “Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts.” That has left environmentalists not only angry at the oil industry, but also wondering how the narrative might have been different had the industry been honest and open about its early findings.

“It’s increasingly clear that the fossil fuel industry knew a lot more about the causes of climate change—and its effects—much earlier than anyone else,” said Annie Leonard, the executive director of Greenpeace USA, about CIEL’s findings. “It pains me to think how much better shape the planet and vulnerable communities could be in if the fossil fuel industry had taken positive action based on this knowledge instead of trying to profit from it.”

Climate activist Bill McKibben, the founder of 350.org, has been a long-time critic of the oil and gas industry. “The ongoing revelations about the depth of oil industry research into—and obfuscation of—the greatest crisis humans have ever faced are hard to read; thanks to them, we wasted vital time,” he said in a press statement.

In a CIEL video, Muffett explains how “the world’s most powerful industry used science, communications and consumer psychology to shape the public debate over climate change,” noting “it begins earlier, decades earlier than anyone recognized.” He points out that in 1968, API commissioned a report titled “Sources, Abundance, and Fate of Gaseous Atmospheric Pollutants,” which revealed rising levels of carbon dioxide, a greenhouse gas produced by the combustion of fossil fuel, in the atmosphere. The report’s authors, Elmer Robinson and R.C. Robbins of the Stanford Research Institute, warned of significant climate risks posed by the continued use of fossil fuel. “If the earth’s temperature increases significantly, a number of events might be expected to occur including the melting of the Antarctic ice cap, a rise in sea levels, warming of the oceans, and an increase in photosynthesis,” they wrote, adding, “there seems to be no doubt that the potential damage to our environment could be severe.”

Notably, Muffett said, is the fact that the report’s authors “recognized that the most important remaining uncertainties were technological: How would we respond and how would we modify our technology to reduce emissions?” Now, nearly half a century later, the question becomes: Why did the oil industry hide this information from the public? Of course, we know the answer to that question: Profits. Instead of responding responsibly to the dire warnings that came with this information by moving the nation’s energy portfolio and infrastructure to a low-carbon future, the oil industry kept on drilling, kept businesses and consumers burning their primary retail products, which continued to pollute the environment and damage the Earth’s climate.

Seventy years of denial and deception

The question for Schneiderman and his fellow state attorneys general is, did ExxonMobil, and possibly other oil companies, intentionally mislead investors, consumer and the public, hiding the damning scientific evidence that their own industry paid to discover? With CIEL’s analysis of industry documents, it appears that Big Oil may be even guiltier than originally suspected, as the group traced the origins of the 1968 API report to a meeting of oil and gas industry executives in Los Angeles more than two decades earlier, in 1946.

That was the year API established the Smoke and Fumes Committee. “Faced with growing public concern about air pollution,” Muffett said, “the industry embarked on what would become a well-funded, carefully coordinated, multi-decade enterprise of funding scientific research and using that research to promote public skepticism of environmental regulations the industry considered hasty, costly and potentially unnecessary.”

One of the tactics used by the oil industry was to delay any climate action that might harm its business by sowing seeds of doubt. “The worst thing that can happen, in many instances, is the hasty passage of a law or laws for the control of a given air pollution situation,” wrote Vance Jenkins, executive secretary of the Smoke and Fumes Committee, in a 1954 trade journal article about smog pollution.

The ties between the oil and tobacco industries run deep. In the 1950s, Monroe J. Rathbone, the president and director of Standard Oil, sat on American Cancer Society’s committee on smoking and public policy. In 1968, Esso Research and Engineering Co., an affiliate of Standard Oil, filed a patent claim for a new type of cigarette filter, made out of polypropylene, a thermoplastic polymer that was first synthesized by Phillips Petroleum, an American Oil Company. In 1979, R.G Baker, the chair of British American Tobacco, the second largest tobacco company in the world, also sat on the board of Exxon, the world’s biggest publicly traded oil company. In the 1970s, R.J. Reynolds, America’s second-largest tobacco company, diversified into the energy business, acquiring American Independent Oil Company, Burmah Oil and Gas Company and Burmah Oil Development, Inc.

In a CIEL video, Muffett explains the key events that reveal the oil industry didn’t just borrow the tobacco industry’s playbook, but was actually behind behind it all along:

As evidence mounts of the oil industry’s decades-long campaign of climate deception and denial, Exxon and its allies assure us that oil is not the new tobacco. The 14 million documents at the Tobacco Archives prove Exxon right: Oil is not the new tobacco. But six decades ago, tobacco was the new oil. In December 1953, tobacco executives met in a New York hotel room to hatch a plan to confront the rising tide of science linking smoking with cancer. To help craft that plan, tobacco turned to PR firm Hill and Knowlton. Hill and Knowlton, in turn, drew on its long expertise supporting the oil industry. Richard Darrow, the principal architect of tobacco’s strategy, also represented Hill and Knowlton’s biggest oil company clients.

In the years that followed, the tobacco conspirators looked repeatedly to oil industry campaigns on smog, lead and other air pollutants for models, for resources and for people. They turned to Stanford Research Institute, a key player in the oil industry’s “Smoke and Fumes” effort to develop a suitcase-sized testing kit that would sample smoke without attracting attention. They turned to Truesdail Laboratories, which in 1958 was doing the earliest documented climate research for the American Petroleum Institute, and to a former Standard Oil executive who recommended an array of scientists for the tobacco industry’s scientific advisory board, nearly all with proven links to the oil industry and many of whom would go on to work for tobacco.

Suffice it to say, CIEL’s analysis has uncovered the deep and complex relationship between the oil and tobacco industries that goes back many decades, and continues to this day. From advertising campaigns and marketing tactics to PR firms and scientists, the two industries have shared a wealth of information, strategies and human resources. The relationship was formed on mutual dependence, which consistently placed profits above public and environmental health. As Muffett points out, “For Big Tobacco, gas stations were vital retail outlets. For Big Oil, cigarettes were their biggest retail product after gasoline.”

“These documents are the tip of an evidentiary iceberg that demands further investigation,” said Muffett. “Oil companies had an early opportunity to acknowledge climate science and climate risks, and to enable consumers to make informed choices. They chose a different path. The public deserves to know why.”

The investigation continues

ExxonMobil and its allies on Capitol Hill—a coterie of GOP legislators who have received political contributions from the oil industry—have attempted to stop the AGs’ fraud probe by claiming the investigation is a violation of the company’s First Amendment rights.

In June, ExxonMobil filed a complaint in federal district court in Fort Worth, Texas, against Massachusetts Attorney General Maura Healey, who had subpoenaed the company under consumer and securities fraud statutes, in an effort to secure company records going back 40 years. In its lawsuit, which is seeking an injunction to stop Healey’s probe, ExxonMobil said Healey’s investigation is “nothing more than a weak pretext for an unlawful exercise of government power to further political objectives,” adding that the attorney general is “abusing the power of government [and] … has deprived and will continue to deprive ExxonMobil of its rights under the United States Constitution.”

Unfortunately for ExxonMobil, the First Amendment claim has already been discredited. In United States vs Philip Morris Inc., a federal appeals court found that the First Amendment does not protect fraudulent statements. Likewise, Healey’s office has dismissed ExxonMobil’s claims.

“For many months, ExxonMobil has engaged in an unprecedented effort to limit the ability of state attorneys general to investigate fraud and unfair business practices,” said Cyndi Roy Gonzalez, Healey’s communications director.

“Our investigation is based not on speculation but on inconsistencies about climate change in Exxon documents which have been made public,” Gonzalez said, and echoing the tobacco lawsuit, added that “the First Amendment does not protect false and misleading statements in the marketplace. Exxon’s assertion that we cannot investigate it because the company has not engaged in business here in Massachusetts is completely preposterous.”

However, a similar battle between ExxonMobil and U.S. Virgin Islands Attorney General Claude Walker ended in a ceasefire, as Walker agreed to withdraw a similar subpoena in exchange for ExxonMobil’s withdrawal of its lawsuit against him. Walker’s withdrawal hasn’t been viewed as a setback for the ongoing probe, as legal experts contend that the primary battlefields will be Massachusetts and New York. So far, Exxon is cooperating with New York’s investigation and has already relinquished more than 700,000 pages of documents to Schneiderman’s office.

But 100 or so recently analyzed documents may reveal the true origin of Big Tobacco’s infamous playbook.

Watch CIEL’s “Smoke and Fumes” videos to learn more about its analysis of those documents: